lt6109-1 Linear Technology Corporation, lt6109-1 Datasheet - Page 15
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lt6109-1
Manufacturer Part Number
lt6109-1
Description
High Side Current Sense Amplifer With Reference And Comparators
Manufacturer
Linear Technology Corporation
Datasheet
1.LT6109-1.pdf
(28 pages)
APPLICATIONS INFORMATION
above the positive supply to 33V below it. These operat-
ing voltages are limited by internal diode clamps shown
in Figures 1 and 2. On supplies less than 35.5V, the lower
range is limited by V
supply, V
supply as shown in Figure 7. Figure 8 shows the range of
operating voltages for the SENSELO and SENSEHI inputs,
for different supply voltage inputs (V
SENSEHI range has been designed to allow the LT6109 to
monitor its own supply current (in addition to the load),
as long as V
Figure 9.
Minimum Output Voltage
The output of the LT6109 current sense amplifier can
produce a non-zero output voltage when the sense voltage
is zero. This is a result of the sense amplifier V
forced across R
Voltage Error, ∆V
effect of the input offset voltage on the transfer function
for parts at the V
zero input sense voltage produces an output voltage. With
a positive offset voltage, the output voltage is zero until
the input sense voltage exceeds the input offset voltage.
Neglecting V
tion of pull-down circuitry and can reach 0V.
Response Time
The LT6109 amplifier is designed to exhibit fast response
to inputs for the purpose of circuit protection or current
monitoring. This response time will be affected by the
external components in two ways, delay and speed.
V
Figure 7. V
BATT
R
I
SENSE
SENSE
R
IN
BATT
10
1
+
OS
SENSE
SENSEHI
SENSELO
LT6109
, to be separate from the LT6109 positive
Powered Separately from Load Supply (V
, the output circuit is not limited by satura-
IN
OS
OUT(VOS)
as discussed previously in the Output
is less than 200mV. This is shown in
limits. With a negative offset voltage,
–
+ 2.5V. This allows the monitored
–
+
section. Figure 10 shows the
V
+
9
V
V
5
+
–
+
). The SENSELO and
OUTA 8
610912 F07
OS
R
OUT
BATT
being
V
OUT
)
Figure 10. Amplifier Output Voltage vs Input Sense Voltage
V
Figure 8. Allowable SENSELO, SENSEHI Voltage Range
BATT
Figure 9. LT6109 Supply Current Monitored with Load
2.9V
2.5V
R
60
50
40
30
27
20
10
I
SENSE
SENSE
R
IN
2.7
120
100
80
60
40
20
10
0
1
0
G = 100
SENSEHI
SENSELO
LT6109
10
100
20.2V
200
V
INPUT SENSE VOLTAGE (µV)
LT6109-1/LT6109-2
OS
300
20
= –350µV
V
400
OS
–
+
= 350µV
V
500
+
30 35.5 40
(V)
9
V
V
5
600
40.2V
+
–
700
800
VALID SENSELO/
SENSEHI RANGE
610912 F10
900
50
1000
OUTA 8
610912 F09
610912 F08
60
15
R
OUT
610912f
V
OUT